Interlocking modular ladder-type cable tray

ABSTRACT

A ladder-type cable tray ( 10 ) for cables or the like, the ladder including one or more pairs of L-shaped side rail members ( 11 ) having vertical and horizontal sides, the vertical side ( 12 ) having formed therein a protruding spring tab ( 14 ) disposed above a socket ( 16 ); and one or more U-shaped rung members ( 22 ) formed at either end with a flange ( 23 ) enclosing a U-shaped opening and defining a folded edge terminating in at least one tooth ( 24 ), the folded edge having formed therein a slot ( 26 ) for engaging the spring tab ( 14 ), such that upon insertion of the rung member ( 22 ) tooth into the socket on the side-rail ( 11 ), the spring tab ( 14 ) is deflected laterally and returns to its position to engage the locking slot ( 26 ) in the rung ( 22 ) and lock the rung to the side-rail ( 11 ), the locked rung ( 22 ) forming a support platform for the cable in a rigid fashion.

FIELD OF THE INVENTION

The present invention relates to cable trays and in particular toladder-type cable trays with interlocking design of modular units formany cabling applications.

BACKGROUND OF THE INVENTION

Cable ladders are commonly used in many wire and cabling applications,for example, in power distribution systems, communications centers, dataprocessing and industrial installations to support the extensive cablingsystems necessary in these applications. Ladder-type construction isopen to all sides and allows easy access to cables which frequently haveto be checked or rerouted.

Current cable ladders are constructed of heavy steel bolted or fastenedtogether into extended runs. Components are often large and bulky.Construction of the system or chances in the construction requiresconsiderable effort to use fasteners to connect each rung to theside-rails.

U.S. Pat. No. 5,465,929 to Dooley and U.S. Pat. No. 5,580,014 toRinderer both disclose ladder-type cable tray systems which requirefasteners. U.S. Pat. No. 4,319,724 to Bradbury discloses a ladder-typecable tray with rungs which are disposed in slots on the side-rails fora friction fit In this construction, the rungs must be placed in theside-rails during assembly and may not be removed from the side-railwithout dissassembling the side-rail, which requires detaching it fromthe support surface This makes modification difficult In addition, thedesign of the Bradbury patent requires the user to cut side-rails andrungs to the desired length and does not provide a modular constructionadaptable to different uses.

Thus it would be desirable to provide a ladder-type cable tray whichwould be lightweight, simple to construct, without requiring fasteners,and easy to transport and store.

SUMMARY OF THE INVENTION

Accordingly, it is a principal object of the present invention toovercome disadvantages associated with prior art and provide aninterlocking, modular ladder-type cable tray which is quickly assembledand simple to install and uninstall and does not require fasteners forthe rungs. Its modular construction allows for the use of smallercomponents, offering the advantages of ease in transport and storage,and the ability to make changes in layout as necessary.

In accordance with a preferred embodiment of the present invention,there is thus provided a ladder-type cable tray for cables or the like,the ladder including:

one or more pairs of L-shaped side-rail members having vertical andhorizontal sides, the vertical side having formed therein a protrudingspring tab disposed above a socket;

one or more U-shaped rung members formed at either end with a flangeenclosing a U-shaped opening and defining a folded edge terminating inat least one tooth, the folded edge having formed therein a slot forengaging the spring tab;

such that upon insertion of the rung member tooth into the socket on theside-rail, the spring tab is deflected laterally and returns to itsposition to engage the locking slot in the rung and lock the rung to theside-rail, the locked rung forming a support platform for the cables ina rigid fashion.

In a preferred embodiment of the invention, a ladder-type cable tray isprovided including two generally parallel L-shaped side-railsinterlocked with one or more cross-pieces forming a ladder rung. Therungs interlock in a non-rotational manner so as to provide stability tothe ladder.

The side-rail is formed with a spring tab, a C-shaped socket and two ormore apertures. The rung is provided on each end with a locking slot forengaging the spring tab, and is provided with two or more teeth, two ormore pins and a notch. The ladder-type cable tray is assembled byinserting the teeth of the rung into the C-shaped sockets on a pair ofoppositely-facing side-rails and depressing the rung, so that the springtab is deflected laterally and returns to its position, becoming engagedin the locking slot formed in the rung. The teeth prevent rotation andslippage of the rung. As the rung is depressed the pins on the rung areinserted into the apertures formed on the side-rail. When the rung abutsthe side-rail, a notch formed on the outer edge of the rung allows thepins to be fully inserted into the apertures formed on the side-rail, sothat the rung becomes seated securely on the side-rail as the notch edgeabuts the side-rail edge. In this interlocked engagement, the insertionof the teeth in the C-shaped socket and the insertion of the pins in theapertures cause the notch edge to abut the side-rail edge and form arigid construction which prevents relative rotation or movement betweenthe rung and the side-rail.

The ladder can be mounted in a vertical or horizontal fashion, and inareas with limited accessibility. Side-rails can be constructed withbends of any angle for construction of systems which bend and turn.Rungs can be mounted in any order along the side-rails during assemblyand installation. For disassembly purposes, the spring tab is depressedso as to disengage the spring tab from the locking slot enablingclearance for removal of the rung from its position in the ladder-typecable tray. The lack of tools needed to do this and the ease with whichdisassembly can be accomplished allows the user the ability to makeadjustments to the cable tray as needed with a minimum of effort

One or more of the side-rails is attached to a wall by means of mountingholes provided on the side-rail Additional mounting holes may beprovided for optional mounting alternatives.

In a preferred embodiment, the side-rails are mounted in a staggeredfashion such that the junctions between the side-rails are not oppositeone another. This provides greater strength to the cable trayconstruction.

Other features and advantages of the invention will become apparent fromthe following drawings and description.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, with regard to theembodiments thereof, reference is made to the accompanying drawings, inwhich like numerals designate corresponding or sections throughout, andin which:

FIG. 1 shows an overview of an interlocking modular ladder-type cabletray constructed in accordance with the principles of the presentinvention;

FIG. 2 is a perspective view of one end of a side-rail of the cable trayof FIG. 1;

FIGS. 3a-c show, respectively, front, side cross-sectional and top viewsof one end of a side-rail;

FIG. 4 is a prespective view of a rung of the cable tray of FIG. 1;

FIGS. 5a-c show, respectively, end, side cross-sectional and top viewsof one end of a rung;

FIGS. 6a and 6 b are perspective views illustrating the insertion of oneend of a rung into a side-rail;

FIGS. 7a and 7 b illustrate the insertion of a rung between twoside-rails, and FIG. 7c shows a top view of a rung inserted between twoside-rails; and

FIG. 8 illustrates an interlocking modular ladder-type cable trayconstructed with a staggered layout of the side-rails

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring now to FIG. 1, there is shown an overview of an interlockingmodular ladder-type cable tray 10 with sections A1, B1, and C1, eachhaving a different orientation, showing the layout flexibility of theinventive cable tray. Vertical section A1 rises vertically and isconnected to horizontal section B1. Horizontal section B1 is connectedto horizontal section C1 via a curved section, for orientation at a 90°angle.

In FIG. 2 there is shown a perspective view of one end of side-rail 11which is provided as an L-shaped beam with vertical and horizontalsides. Vertical side 12 is formed with spring tab 14 and C-shaped socket16. Horizontal side 18 is formed with at least two apertures 20.

In FIG. 3a there is shown a front view of side-rail 11, showing springtab 14 and C-shaped socket 16 provided on vertical side 12. FIG. 3bshows a cross-section of side-rail 11 along section lines IIIb—IIIb ofFIG. 3a, showing spring tab 14 and C-shaped socket 16 on vertical side12, and aperture 20 on horizontal side 18. In FIG. 3c a top view ofside-rail 11 is shown, featuring spring tab 14, C-shaped socket 16 andapertures 20.

In FIG. 4, there is shown a perspective view of rung 22. Rung 22 isprovided as a U-shaped section with flange 23 folded over at its endsdefining folded edges, having formed therein at least two teeth 24 and alocking slot 26. At least two pins 28 and notch 30 are provided on eachof side surfaces 31 of rung 22 proximate its ends.

Referring now to FIG. 5a, there is shown an end view of rung 22, formedwith teeth 24 and locking slot 26. FIG. 5b shows a cross-sectional sideview along section lines Vb—Vb, of FIG. 5a. The layout of tooth 24,locking slot 26, pin 28 and notch 30 are shown. FIG. 5c is a top view ofrung 22 formed with locking slot 26.

FIGS. 6a-b show a perspective view illustrating the insertion of rung 22into side-rail 11 as a part of the inventive assembly method, as will befurther described in FIGS. 7a-b. After rung 22 has been inserted, FIG.6b shows the resulting arrangement in which spring tab 14 is insertedinto locking slot 26, teeth 24 are inserted in C-shaped socket 16, pins28 are inserted in apertures 20, and notch 30 is fitted onto horizontalside 18 such that notch edge 32 abuts side-rail edge 34.

FIGS. 7a-b show the assembly method in greater detail. In FIG. 7a, thedirection of insertion of rung 22 into side-rail 11 is indicated byarrows A. Upon assembly of the cable tray, teeth 24 on rung 22 areinserted into C-shaped socket 16 on side-rail 11, causing spring tab 14to be deflected laterally. Preferably, spring tab 14 is formed so as tobe sufficiently resilient such that it returns to its initial alignmentonce rung 22 has been fully inserted in portion, so as to becomeinserted in locking slot 26 in rung 22, thereby locking the rung 22 withrespect to side-rail 11. Alternatively, however, spring tab 14 may be ofreduced resilience, such that it may have to be bent into lockingengagement with locking slot 26, such as by use of a screwdriver or thelike.

Pins 28 on rung 22 are inserted into apertures 20 on side-rail 11. Notch30 on rung 22 allows pins 28 to be fully inserted into apertures 20 onside-rail 11. In this interlocked engagement, the insertion of teeth 24in C-shaped socket 16 and the insertion of pins 28 in apertures 20 causenotch edge 32 to abut side-rail edge 34 and form a rigid constructionwhich prevents relative rotation or movement between the rung and theside-rail.

To disassemble the cable tray, spring tab 14 is depressed, in somecases, by conveniently inserting a screwdriver, so as to disengagespring tab 14 from locking slot 26, enabling clearance for removal ofrung 22 from its position between side-rails 11.

Once assembled, FIG. 7b shows a cross-sectional view of rung 22 insertedbetween two side-rails 11, in which spring tab 14 is inserted intolocking slot 26, teeth 24 are inserted in C-shaped socket 16, pins 28are inserted in apertures 20, and notch 30 is fitted onto horizontalside 18. Arrows B and D are marked to indicate that motion in theindicated directions is prevented by the insertion of rung 22 intoside-rails 11. FIG. 7c shows a top view of rung 22 inserted between twoside-rails 11 such that motion in the direction of arrows E is notpossible.

In FIG. 8, a preferred embodiment of the cable tray is shown, such thatjunctures 40 and 42 between adjacent side-rails are not opposite to eachother. This construction features staggered assembly of side-rails 11providing greater strength.

Having described the invention with regard to specific embodimentsthereof it is to be understood that the description is not meant as alimitation, since further modifications may now suggest themselves tothose skilled in the art, and it is intended to cover such modificationsas fall within the scope of the appended claims.

What is claimed is:
 1. A ladder-type cable tray for cable-like elements,said cable tray including: at least a pair of L-shaped side-rail membershaving vertical and horizontal sides, said vertical side having formedtherein a protruding spring tab disposed above a socket; at least oneU-shaped rung member formed at each end with a flange enclosing aU-shaped opening and defining a folded edge terminating in at least onetooth, said folded edge having formed therein a slot for engaging saidspring tab; such that upon insertion of said rung member tooth into saidsocket on said side-rail member, said spring tab is deflected andreturns to a position to engage said slot in said rung member and locksaid rung member to said side-rail member, said locked rung memberforming a support platform for said cable-like elements in a rigidfashion.
 2. The ladder-type cable tray of claim 1, wherein: saidhorizontal side of each side-rail member is formed with at least oneaperture; and said rung member is formed with at least one pin and anotch at an end thereof; such that upon insertion of said rung pin intosaid side-rail member, an edge of said rung notch abuts said edge ofsaid side-rail member, becoming seated securely on said side-railmember, said locked rung member forming a stable non-rotatable supportplatform.
 3. The ladder-type cable tray of claim 1, wherein saidside-rail members form at least two substantially parallel runs of saidside-rail members with adjacent side-rail members abutting one anotherat a junction, said runs being positioned such that the junction of theends of said side-rail members on a first run is not opposite thejunction of the ends of said side-rail members on a second run, suchthat said side-rail members are positioned in a staggered fashion so asto provide the ladder-type cable tray with added stability and strength.4. The ladder-type cable tray of claim 1, wherein sections thereof areoriented in at least one of vertical and horizontal orientations or atan angle therebetween.
 5. The ladder-type cable tray of claim 1, whereinsaid at least one rung member and said side-rail members are provided asinterlocking modular units.
 6. A method for assembling a ladder-typecable tray for cable-like elements, said method comprising: providing atleast a pair of L-shaped side-rail members having vertical andhorizontal sides, said vertical side having formed therein a protrudingspring tab disposed above a socket; providing at least one U-shaped rungmember formed at either end with a flange enclosing a U-shaped openingand defining a folded edge terminating in at least one tooth, saidfolded edge having formed therein a slot for engaging said spring tab;and inserting said rung member tooth into said socket on said side-railmember, such that said spring tab is deflected and returns to a positionto engage said slot in said rung member and lock said rung member tosaid side-rail member, said locked rung member forming a supportplatform for said cable-like elements in a rigid fashion.
 7. The methodfor assembling the ladder-type cable tray for cable-like elementsaccording to claim 6, further comprising: inserting a pin formed in anend of said rung member into an aperture formed in said horizontal sideof said side-rail member such that a notch on an end of said rung memberabuts an edge of said side-rail member, locking said rung membertherein, forming a stable non-rotatable support platform.
 8. The methodfor assembling the ladder-type cable tray for cable-like elementsaccording to claim 6, further comprising: positioning said side-railmembers adjacent to one another to form at least two substantiallyparallel runs of said side-rail members with adjacent side-rail membersabutting one another at a junction, said runs being positioned such thatthe junction of the ends of said side-rail members on a first one of theruns is not opposite the junction of the ends of said side-rail memberson a second one of the runs, such that said side-rail members arepositioned in a staggered fashion so as to provide the ladder-type cabletray with added stability and strength.